4
There are four sevens in twenty-eight, as 28 divided by 7 equals 4. This means you can fit four groups of seven into twenty-eight without any remainder.
Asking what one eighth of twenty-seven is, is basically the same as asking what twenty-seven divided by eight is, and therefore the answer is '3.375'. I have put the answer in inverted commas so that it does not look like the fullstop is a second decimal point.
55
seven twenty-fourths
81